1. Technical Field
The present invention relates to a paper coloring apparatus for coloring a paper sheet on which an image is formed, and to an image forming system where an image forming apparatus and/or a book binding apparatus are connected to the paper coloring apparatus.
2. Description of Prior Art
As the paper sheets to be used in the image forming apparatus, commonly used are paper sheets of white color or colors of nearly white.
However, there are requirements of taking on suitable colors such as yellow, green or red for the paper sheets, in order to attain special effects.
To respond these requirements, it is needed to previously prepare various colored paper sheets, and to load a prescribed colored paper sheet on a prescribed sheet tray before starting the image forming operation.
However, to previously prepare many various colored paper sheets suitable for the requirement may cause a cost increase, as well as a heavy load for management.
In order to lessen these inconveniences, it has been considered to execute image formation subsequently to coloring a white paper sheet, or to color the paper sheet subsequently to the image formation.
As an apparatus for coloring a paper sheet, an apparatus which colors Japanese paper by inkjet system is disclosed for example in Unexamined Japanese Patent Application Publication No. H10-44388.
However, in utilizing the inkjet system, dissatisfaction in processing speed will be remarkable in cases where almost an entire surface of the paper sheet is to be colored, or both faces of the paper sheet are to be colored.
As an apparatus which coats liquid on a paper sheet after image formation, an apparatus which applies perfume onto a photographic paper sheet after development process is disclosed for example.
However, since applying perfume on the photographic paper does not require uniform coatings to both faces of the paper sheet, the configuration of the apparatus disclosed in Unexamined Japanese Patent Application Publication No. 2003-215772 cannot be directly adapted to an apparatus for coloring a paper sheet.